Pressure measurement in highly deviated wells

ABSTRACT

A pressure measurement system for use with a subterranean well can include a chamber positioned in the well, the chamber having an upper portion and a lower portion as positioned in the well, and a device which, in response to gravity acting on the device, selects the upper portion of the chamber for communication with a line extending to a remote location. A method of measuring pressure in a well can include introducing a chamber into the well, then selecting a vertically upper portion of the chamber, and establishing communication between the upper portion of the chamber and a line extending to a remote location.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.12/964,587 filed on 9 Dec. 2010. The entire disclosure of this priorapplication is incorporated herein by this reference.

BACKGROUND

This disclosure relates generally to equipment utilized and operationsperformed in conjunction with a subterranean well and, in an exampledescribed below, more particularly provides for pressure measurement inhighly deviated wells.

In a conventional technique for measuring pressure in a wellbore, asmall diameter tube is connected to a top of a chamber in the wellbore,and a bottom of the chamber is exposed to wellbore pressure. Pressurizedgas is applied to the tube at the surface to fill the chamber with gas.Measurement of pressure in the tube at the surface enables wellborepressure to be conveniently determined.

Unfortunately, such a system suffers from disadvantages when it isdesired to measure pressure in a wellbore which is highly deviated fromvertical. Especially in a horizontal or near-horizontal wellbore, such asystem can be unusable.

Therefore, it will be appreciated that improvements are needed in theart of pressure measurement in highly deviated wells.

SUMMARY

In the disclosure below, systems and methods are provided which bringimprovements to the art of pressure measurement in highly deviatedwells. One example is described below in which a weighted blockingdevice is used to selectively block communication ports in a wellpressure measurement system. Another example is described below in whichthe device selectively establishes communication between upper and lowerportions of a chamber and respective pressure sources.

In one aspect, a pressure measurement system for use with a subterraneanwell is provided to the art by this disclosure. The system can include achamber positioned in the well, and the chamber having an upper portionand a lower portion as positioned in the well. A device selects theupper portion of the chamber for communication with a line extending toa remote location, in response to gravity acting on the device.

In another aspect, a method of measuring pressure in a well is providedby this disclosure. The method can include: introducing a chamber intothe well; then selecting a vertically upper portion of the chamber; andestablishing communication between the selected upper portion of thechamber and a line extending to a remote location.

The lower portion of the chamber can be placed in communication with awellbore or other pressure source for which it is desired to measure itspressure. The upper and lower portions of the chamber are notdetermined, until the chamber is positioned in the well.

These and other features, advantages and benefits will become apparentto one of ordinary skill in the art upon careful consideration of thedetailed description of representative examples below and theaccompanying drawings, in which similar elements are indicated in thevarious figures using the same reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are representative cross-sectional views of a prior art methodof measuring pressure in a wellbore.

FIG. 4 is a representative cross-sectional view of a pressuremeasurement apparatus which can embody principles of the presentdisclosure.

FIGS. 5 & 6 are cross-sectional views of the pressure measurementapparatus, taken along respective lines 5-5 and 6-6 of FIG. 4.

FIG. 7 is a representative cross-sectional view of the apparatus asactivated for pressure measurement.

FIGS. 8-11 are representative cross-sectional views of additionalconfigurations of the apparatus.

FIG. 12 is a representative cross-sectional view of a furtherconfiguration of the apparatus.

FIGS. 13 & 14 are cross-sectional views of the apparatus, taken alongrespective lines 13-13 and 14-14 of FIG. 12.

DETAILED DESCRIPTION

Illustrated in FIGS. 1-3 is a prior art system 10 and associated methodfor measuring pressure in a wellbore 14. In the system 10, a chamber 12is lowered into the wellbore 14 connected to a line 16. A pressurizedgas 18 is then forced down the line 16 and into the chamber 12,displacing well fluid 20 out of the chamber 12.

In FIG. 1, the system 10 is depicted after the well fluid 20 has beendisplaced completely out of the chamber 12. At this point, pressure inthe gas 18 balances pressure in the well fluid 20 at the chamber 12. Ifpressure in the well fluid 20 increases, the gas 18 will be compressed,and the well fluid will enter the chamber 12 as depicted in FIG. 2.Since the pressure in the gas 18 continues to balance pressure in thewell fluid 20, this increase in pressure in the well fluid can bedetected by monitoring the pressure in the gas 18 via the line 16, whichextends to a remote location, for example, to the earth's surface. Thistype of pressure measurement is described in U.S. Pat. No. 4,010,642,the entire disclosure of which is incorporated herein by this reference.

The system 10 performs well in substantially vertical wellbores, such asthe wellbore 14 depicted in FIGS. 1 & 2. However, if the chamber 12 ispositioned in a wellbore 22 which is horizontal or at leastsubstantially deviated from vertical, as depicted in FIG. 3, seriousproblems develop in the system 10. For example, the usable volume of thechamber 12 is significantly reduced, which substantially limits therange of pressures in the well fluid 20 which may be measured using thesystem 10. As another example, there is the danger that the well fluid20 will enter the line 16, plugging the line and requiring replacement,or at least retrieval and cleaning, of the line at substantial expense.

It is generally considered that the system 10 cannot be used inwellbores which are deviated from vertical greater than about 70°.Significant problems may be experienced when the system 10 is used inwellbores deviated greater than about 60°. As used herein, the term“substantially deviated” is used to describe wellbores which aredeviated greater than about 50° from vertical.

It has become increasingly common for wellbores to be drilledhorizontally and at other substantial deviations from vertical. Thesystem 10 as depicted in FIGS. 1-3 is largely unsuitable for use inthese wellbores, and so there is a need for an improved method ofmeasuring pressure in substantially deviated wellbores. Some wellboresare even drilled past horizontal, that is, the wellbores incline upwardin the direction in which they are drilled. It will be appreciated thatthe system 10 is completely unusable in these wellbores drilled pasthorizontal, since the chamber 12 would fill with well fluid 20, and wellfluid would enter the line 16.

Representatively illustrated in FIG. 4 is a well pressure measurementapparatus 30 and associated method which can embody principles of thisdisclosure. The apparatus 30 can be used in an improvement to the system10 and method described above. Of course, the apparatus 30 can be usedin other systems and methods while remaining within the scope of thisdisclosure.

As depicted in FIG. 4, the apparatus 30 includes the chamber 12described above. The chamber 12 of the apparatus 30 is annular shapedand is positioned radially between a tubular outer housing 32 and atubular inner housing 34. The chamber 12 also extends longitudinallybetween annular bulkheads 36, 38 at its opposite ends. However, chambershaving other shapes can be used, if desired.

In a non-vertical orientation of the apparatus 30 as depicted in FIG. 4,it will be appreciated that the chamber 12 has a vertically upperportion 12 a and a vertically lower portion 12 b. However, which portionof the chamber 12 will be the upper portion 12 a, and which will be thelower portion 12 b, is unknown when the apparatus 30 is installed in thewellbore 14. The inner housing 34 is designed for interconnection in atubular string (such as a production tubing string), and the tubularstring can rotate when it is installed.

Since the line 16 should be in communication with the chamber upperportion 12 a and the chamber lower portion 12 b should be incommunication with the wellbore 14 for effective pressure measurement,but the rotational orientation of the chamber 12 after installation isnot known until after installation, the apparatus 30 provides forselecting the chamber upper portion 12 a for communication with the line16 and selecting the chamber lower portion 12 b for communication withthe wellbore 14 after installation of the apparatus in the well.

The selection of which portion of the chamber 12 will be placed incommunication with the line 16 is performed by a weighted blockingdevice 40 in conjunction with multiple ports 42 formed through thebulkhead 36. The ports 42 in this example are plugged with plugs 44which can be blocked by the device 40.

All of the ports 42 are plugged by the plugs 44, as depicted in theas-installed state of the apparatus 30 in FIG. 4. Thus, the line 16 isnot in communication with any portion of the chamber 12.

However, if pressure in the line 16 is sufficiently increased, the plugs44 will be biased to the right as viewed in FIG. 4. Some, but not all,of the plugs 44 will be blocked by the device 40, and will thereby beprevented from being pushed out of the ports 42 by the pressure appliedto the line 16.

The cross-sectional view of FIG. 5 shows how the device 40 blocks someof the plugs 44, but does not block others of the plugs. Note that theplug 44 which is vertically highest relative to the other plugs is notblocked by the device 40, but the lowermost plugs are blocked by thedevice.

The device 40 is retained radially between the inner and outer housings32, 34, but is permitted to displace vertically relative to the chamber12 and the vertically distributed ports 42 and plugs 44. In this manner,gravity acting on the device 40 causes it to be positioned opposite thelower ports 42 and plugs 44, but not the uppermost port and plug.

The device 40 is depicted in FIGS. 4-6 as being annular shaped, butother shapes and configurations are possible within the scope of thisdisclosure. Some further examples are depicted in FIGS. 8-11, but itshould be clearly understood that no particular shape or configurationof the device 40 is required in keeping with the principles of thisdisclosure.

The cross-sectional view of FIG. 6 shows how another similar device 46selectively blocks ports 48 and plugs 50 in the bulkhead 38. However, inthis case, the device 46 blocks the upper ports 48 and plugs 50, butdoes not block the lowermost port and plug. Thus, if sufficient pressureis applied to the chamber 12, the lowermost plug 50 can be ejected fromthe lowermost port 48, but the device 46 will prevent the other plugsfrom being ejected from their respective ports.

Referring additionally now to FIG. 7, the apparatus 30 is depicted afterincreased pressure has been applied to the line 16 from a remotelocation (such as a pressurized source of the gas 18 at the surface).Note that the uppermost plug 44 has been ejected from the uppermost port42 in the bulkhead 36. This allows the increased pressure to enter thechamber 12.

The increased pressure in the chamber 12 has ejected the lowermost plug50 from the lowermost port 48 in the bulkhead 38. The increased pressurehas, thus, been allowed to act on a rupture disc 52 which previouslyisolated the interior of the apparatus 30 from wellbore pressure.

When the increased pressure is sufficiently great, the rupture disc 52will rupture, thereby exposing the chamber 12 to wellbore pressure. Theapparatus 30 can now be used to measure pressure in the wellbore 14,because the line 16 is in communication via the opened port 42 with theupper portion 12 a of the chamber 12, and the lower portion 12 b of thechamber is in communication with the wellbore 14 via the open port 48and the ruptured disc 52.

Note that the plugs 44, 50 could be releasably secured in theirpositions in the bulkheads 36, 38 by use of shear pins, snap rings,latches, etc., to maintain the positions of the plugs until apredetermined pressure differential is applied to the plugs.

In the example of the apparatus 30 described above, the devices 40, 46have inner and outer diameters selected so that the devices block therespective upper or lower ports 42, 48 in the bulkheads 36, 38. However,other configurations may be used, if desired, to selectively block theports 42, 48 which should not be opened when increased pressure isapplied to the line 16. Examples of other configurations arerepresentatively illustrated in FIGS. 8-11.

In FIG. 8, the device 40 comprises many small balls 54 which will fallto a lower side of the bulkhead 36 to block the lower ports 42.

In FIG. 9, the device 46 is somewhat annular shaped, but has athickened, heavier weight, portion with a window 56 to align with thelowermost port 48 and plug 50 in the bulkhead 38.

In FIG. 10, the device 40 comprises multiple discs 58 which will rolltoward the lower side of the bulkhead 36 to block all but the uppermostport 42 and plug 44.

In FIG. 11, the device 40 has an annular shape, but it also has aflattened side 60 which ensures that the device does not block theuppermost port 42 and plug 44 in the bulkhead 36.

It will, thus, be readily appreciated that the scope of this disclosureis not limited to any particular device configuration, placement, etc.Instead, it should be clearly understood that any type of device whichcan block flow through all but the uppermost of the ports 42, and/or allbut the lowermost of the ports 48, may be used in the apparatus 30 orother pressure measurement apparatuses. For example, the devices 40, 46could block flow through the respective lowermost ports 42 and uppermostports 48 by sealing off the ports, etc.

The device 40 can allow flow through more than one of the ports 42, andthe device 46 can allow flow through more than one of the ports 48, ifdesired. Thus, it is not necessary for the devices 40, 46 to block flowthrough all but one of the respective ports 42, 48.

The ports 42, 48 are vertically distributed after the apparatus 30 isinstalled in the wellbore 14, in that some of the ports 42 arevertically higher than others of the ports 42, and some of the ports 48are vertically higher than others of the ports 48. This verticaldistribution is accomplished in the illustrated examples by spacing theports 42, 48 in circular patterns through the respective bulkheads 36,38. However, it should be clearly understood that other ways ofvertically distributing the ports 42, 48 may be used, if desired.

In the examples described above, the bulkheads 36, 38 are positioned onopposite ends of the chamber 12, and separate devices 40, 46 are used toblock flow through the respective ports 42, 48. In other examples,however, these relative positions of the bulkheads 36, 38 and thechamber 12, and the use of separate devices 40, 46, are not necessary.

In FIGS. 12-14, a configuration of the apparatus 30 is representativelyillustrated, in which the bulkheads 36, 38 are positioned on one side ofthe chamber 12, and a single device 62 is used to selectively block flowthrough the uppermost ports 48 and the lowermost ports 42. It will,thus, be readily appreciated that a variety of different configurationsof the apparatus 30 may be used, in keeping with the scope of thisdisclosure.

In any of the configurations of the apparatus 30 described above, theapparatus can be reversed if it will be positioned in a wellbore whichis deviated more than 90 degrees from vertical.

It may now be fully appreciated that the above disclosure andaccompanying drawings provide several advancements to the art ofpressure measurement in wells. In the examples of the apparatus 30described above, the chamber 12 can be used to measure pressure inhighly deviated wells, even though the post-installation rotationalorientation of the chamber is not known before installation.

In particular, the above disclosure provides to the art a pressuremeasurement system 10 for use with a subterranean well. The system 10can include a chamber 12 positioned in the well, and the chamber 12having an upper portion 12 a and a lower portion 12 b as positioned inthe well. A device 40 or 62, in response to gravity acting on thedevice, selects the upper portion 12 a of the chamber 12 forcommunication with a line 16 extending to a remote location.

The device 40 or 62 can selectively block less than all of multiplevertically distributed communication ports 42.

The device 40 or 62 may selectively prevent opening of less than all ofthe multiple vertically distributed communication ports 42.

The device 40 or 62 may selectively prevent discharge of plugs 44 fromless than all of multiple vertically distributed communication ports 42.

Communication between the line 16 and the upper portion 12 a of thechamber 12 can be established in response to application of increasedpressure to the line 16. Less than all of multiple verticallydistributed communication ports 42 may be opened in response toapplication of the increased pressure to the line 16.

The lower portion 12 b of the chamber 12 can be selected in the well.Communication between a wellbore 14 and the lower portion 12 b of thechamber 12 can be established in the well. Communication between thewellbore 14 and the lower portion 12 b of the chamber 12 can beestablished in response to application of increased pressure to the line16.

The device 40 or 62 may displace relative to multiple verticallydistributed communication ports 42 in response to gravity acting on thedevice 40 or 62.

Also described by this disclosure is a method of measuring pressure in awell. The method can include introducing a chamber 12 into the well,then selecting a vertically upper portion 12 a of the chamber 12, andestablishing communication between the selected upper portion 12 a ofthe chamber 12 and a line 16 extending to a remote location.

Selecting the vertically upper portion 12 a of the chamber 12 can beperformed by a device 40 or 62 which displaces relative to the chamber12 in response to gravity acting on the device 40 or 62.

Establishing communication can include applying increased pressure tothe line 16. Less than all of multiple vertically distributedcommunication ports 42 may be opened in response to applying increasedpressure to the line 16.

The method can also include selecting a vertically lower portion 12 b ofthe chamber 12 after introducing the chamber 12 into the well. In thatcase, the method can also include establishing communication between awellbore 14 and the lower portion 12 b of the chamber 12 after selectingthe lower portion 12 b of the chamber 12. Establishing communicationbetween the wellbore 14 and the lower portion 12 b of the chamber 12 canbe performed by applying increased pressure to the line 16.

It is to be understood that the various examples described above may beutilized in various orientations, such as inclined, inverted,horizontal, vertical, etc., and in various configurations, withoutdeparting from the principles of the present disclosure. The embodimentsillustrated in the drawings are depicted and described merely asexamples of useful applications of the principles of the disclosure,which are not limited to any specific details of these embodiments.

Of course, a person skilled in the art would, upon a carefulconsideration of the above description of representative embodiments,readily appreciate that many modifications, additions, substitutions,deletions, and other changes may be made to these specific embodiments,and such changes are within the scope of the principles of the presentdisclosure. Accordingly, the foregoing detailed description is to beclearly understood as being given by way of illustration and exampleonly, the spirit and scope of the present invention being limited solelyby the appended claims and their equivalents.

What is claimed is:
 1. A pressure measurement system for use with a subterranean well, the system comprising: a chamber positioned in the well, and the chamber having an upper portion and a lower portion as positioned in the well; and a device which, in response to gravity acting on the device, selects the upper portion of the chamber for communication with a line extending to a remote location, wherein communication between the line and the upper portion of the chamber is established via at least one of multiple vertically distributed communication ports in response to application of increased pressure to the line.
 2. The system of claim 1, wherein the device selectively blocks less than all of the multiple vertically distributed communication ports.
 3. The system of claim 1, wherein the device selectively prevents opening of less than all of the multiple vertically distributed communication ports.
 4. The system of claim 1, wherein the device selectively prevents discharge of plugs from less than all of the multiple vertically distributed communication ports.
 5. The system of claim 1, wherein less than all of the multiple vertically distributed communication ports is opened in response to application of the increased pressure to the line.
 6. The system of claim 1, wherein the lower portion of the chamber is selected in the well.
 7. The system of claim 6, wherein communication between a wellbore and the lower portion of the chamber is established in the well.
 8. The system of claim 7, wherein communication between the wellbore and the lower portion of the chamber is established in response to application of increased pressure to the line.
 9. The system of claim 1, wherein the device displaces relative to the multiple vertically distributed communication ports in response to gravity acting on the device.
 10. A method of measuring pressure in a well, the method comprising: introducing a chamber into the well; then selecting a vertically upper portion of the chamber; and applying increased pressure to a line extending to a remote location, thereby establishing communication between the selected upper portion of the chamber and the line, wherein less than all of multiple vertically distributed communication ports is opened in response to applying the increased pressure to the line.
 11. The method of claim 10, wherein selecting the vertically upper portion of the chamber is performed by a device which displaces relative to the chamber in response to gravity acting on the device.
 12. The method of claim 11, wherein the device selectively blocks less than all of multiple vertically distributed communication ports.
 13. The method of claim 11, wherein the device selectively prevents discharge of plugs from less than all of multiple vertically distributed communication ports.
 14. The method of claim 10, further comprising selecting a vertically lower portion of the chamber after introducing the chamber into the well.
 15. The method of claim 14, further comprising establishing communication between a wellbore and the lower portion of the chamber after selecting the lower portion of the chamber.
 16. The method of claim 15, wherein establishing communication between the wellbore and the lower portion of the chamber is performed by applying the increased pressure to the line. 